mirror of
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48bef4698b
Previously we would just treat each merge marker as trivia and then continue
scanning and parsing like normal. This worked well in some scenarios, but
fell down in others like:
```
class C {
public foo() {
<<<<<<< HEAD
this.bar();
}
=======
this.baz();
}
>>>>>>> Branch
public bar() { }
}
```
The problem stems from the previous approach trying to incorporate both branches of the merge into
the final tree. In a case like this, that approach breaks down entirely. The the parser ends up
seeing the close curly in both included sections, and it considers the class finished. Then, it
starts erroring when it encounters "public bar()".
The fix is to only incorporate one of these sections into the tree. Specifically, we only include
the first section. The second sectoin is treated like trivia and does not affect the parse at all.
To make the experience more pleasant we do *lexically* classify the second section. That way it
does not appear as just plain black text in the editor. Instead, it will have appropriate lexicla
classifications for keywords, literals, comments, operators, punctuation, etc. However, any syntactic
or semantic feature will not work in the second block due to this being trivia as far as any feature
is concerned.
This experience is still much better than what we had originally (where merge markers would absolutely)
destroy the parse tree. And it is better than what we checked in last week, which could easily create
a borked tree for many types of merges.
Now, almost all merges should still leave the tree in good shape. All LS features will work in the
first section, and lexical classification will work in the second.
TypeScript
TypeScript is a language for application-scale JavaScript. TypeScript adds optional types, classes, and modules to JavaScript. TypeScript supports tools for large-scale JavaScript applications for any browser, for any host, on any OS. TypeScript compiles to readable, standards-based JavaScript. Try it out at the playground, and stay up to date via our blog and twitter account.
Contribute
There are many ways to contribute to TypeScript.
- Submit bugs and help us verify fixes as they are checked in.
- Review the source code changes.
- Engage with other TypeScript users and developers on StackOverflow.
- Join the #typescript discussion on Twitter.
- Contribute bug fixes.
- Read the language specification (docx, pdf).
Documentation
Building
In order to build the TypeScript compiler, ensure that you have Git and Node.js installed.
Clone a copy of the repo:
git clone https://github.com/Microsoft/TypeScript.git
Change to the TypeScript directory:
cd TypeScript
Install Jake tools and dev dependencies:
npm install -g jake
npm install
Use one of the following to build and test:
jake local # Build the compiler into built/local
jake clean # Delete the built compiler
jake LKG # Replace the last known good with the built one.
# Bootstrapping step to be executed when the built compiler reaches a stable state.
jake tests # Build the test infrastructure using the built compiler.
jake runtests # Run tests using the built compiler and test infrastructure.
# You can override the host or specify a test for this command.
# Use host=<hostName> or tests=<testPath>.
jake runtests-browser # Runs the tests using the built run.js file. Syntax is jake runtests. Optional
parameters 'host=', 'tests=[regex], reporter=[list|spec|json|<more>]'.
jake baseline-accept # This replaces the baseline test results with the results obtained from jake runtests.
jake -T # List the above commands.
Usage
node built/local/tsc.js hello.ts
Roadmap
For details on our planned features and future direction please refer to our roadmap.